ESMRMB 2009 InfoRESO Fitting Tool for Arrays of Interrelated Datasets (FiTAID) Daniel G.Q. Chong 1 Johannes Slotboom 2 Christine Bolliger 1 Chris Boesch 1 Roland Kreis 1 1 Department of Clinical Research, Unit for MR-Spectroscopy & Methodology, University Bern, 3010 Bern, Switzerland 2 Department of Radiology, Neuroradiology, and Nuclear Medicine, University Hospital Bern, 3010 Bern, Switzerland Slide

Fitting Tool for Arrays of Interrelated Datasets (FiTAID) Interrelated Datasets 2D NMR > 2DJ > COSY, TOCSY... 2DJ Inversion Recovery Kinetics Slide

Linear Combination Model Fitting > Linear combination model for 1D spectra > Linear combination of spectra for interrelated datasets (2D) > Fitting with non-linear least squares minimization Fitting Tool for Arrays of Interrelated Datasets (FiTAID) Hofmann et al. MRM, 2002 Slide

Spectral Array (repeats) > SNR of single measurement is usually poor > Repeats are necessary in order to increase SNR > Summed average spectrum is usually used for model fitting Simplest interrelated data set is array of repeat spectra Assume summed average result to be the gold standard here Fitting Tool for Arrays of Interrelated Datasets (FiTAID) 16 Spectra Array Average Single Slide

Individual vs Array > Comparing individual fit and array fit result to summed average spectrum fit > Individual fit results are spread out due to low SNR; the mean is close to expected value > Array fit is identical to summed average fit > Array fit effectively increased SNR identical to summed average by n:= number of spectra Fitting Tool for Arrays of Interrelated Datasets (FiTAID) Area Same result for fitting as array or as averaged spectrum Slide

Kinetic Study: Histidine through blood-brain barrier > Histidine aromatic resonances at 7.06 and 7.79ppm > Assume only histidine concentration have noticeable changes over time > Spectral array fit with following prior knowledge > 1 st dimension (chemical shift) prior knowledge —Common phase and Gauss line width for each spectrum > 2 nd dimension (time) prior knowledge —Constant amplitude for all peaks except histidine —Constant frequency shift —Constant Lorentz line width Fitting Tool for Arrays of Interrelated Datasets (FiTAID) fit residues Slide

2DJ > Amplitude T 2 decay in 2 nd dimension > Separate simulated metabolite basis sets for each echo time. > T 2 estimation for each metabolite > Separation of metabolite with macromolecule signal by T 2 differences Fitting Tool for Arrays of Interrelated Datasets (FiTAID) Slide

Inversion Recovery > Inversion recovery relationship for amplitude in 2 nd dimension > Combine with two non inverted spectra for accurate frequency and line width estimation > Metabolite and macromolecule signal separation Fitting Tool for Arrays of Interrelated Datasets (FiTAID) Slide

Patterns > Four pattern types —Simple Voigt Line —Parametric Pattern (Collection of Voigt lines) —Numerical Pattern —Metabolite Pattern (Collection of all above) > Hierarchical structure for better metabolite signal separation > Pattern selections for maximum flexibility > Eg. lactate signal with CH quartet and CH 3 doublet can have these combinations of patterns as model Fitting Tool for Arrays of Interrelated Datasets (FiTAID) Slotboom, Proc. Intl. Soc. MRM, Slide

Patterns a. Using metabolite model with separate numerical patterns for CH and CH 3 signal group allows for effects such as water suppression pulse affecting the CH signal b. Single numerical pattern gives larger residue for CH signal even when residue of CH 3 signal is similar to (a) Fitting Tool for Arrays of Interrelated Datasets (FiTAID) Slide

Other Features > Voigt Lines > Time Domain Model > Restricted Parameter Search Space > Time and Frequency Domain Fit > Fit Strategy Steps —Algorithm, Parameter Set, Selected Spectrum and Fit Domain > Platform Independence Fitting Tool for Arrays of Interrelated Datasets (FiTAID) Slide

Graphical User Interface Fitting Tool for Arrays of Interrelated Datasets (FiTAID) Spectral View Dicom Import Modeling Panel Slide

Summary > 2 nd Dimension Prior Knowledge —Any spectral array is possible > 2 nd Dimension Relationship —Saturation Recovery —Inversion Recovery —2DJ > Hierarchical Model with Patterns SNF support Fitting Tool for Arrays of Interrelated Datasets (FiTAID) Slide

Thank you Thank you for watching this slideshow Please take a flyer if you are interested Please us for more information or or You may try out the software on this computer with the “Load test” button to load simple examples and some examples shown in this presentation This slideshow will restart in 10 seconds Fitting Tool for Arrays of Interrelated Datasets (FiTAID) Slide