PURPOSE: Separate assessment of changes in blood oxygenation and blood volume is required in blood oxygen level-dependent (BOLD) imaging. We developed a calculated echo time (TE) imaging technique designed to minimize effects of blood oxygenation and to evaluate blood volume specifically. MATERIALS AND METHODS: Dynamic 3T multi-echo BOLD images of calf muscle were acquired from six healthy volunteers by use of a cuff-compression model. Calculated TE images at TE = 0 ms (cTE0) and T2* map (T2*) were calculated from acquired multi-echo images. The time courses of the mean value for the entire calf muscles in cTE0, in acquired BOLD images at TE = 45.2 ms (aTE45), and in T2* were obtained. The Euclidean distances between the two pairs of time courses were calculated: distance between aTE45 and T2* (D at), and that between cTE0 and T2* (D ct). The difference between D at and D ct was tested by use of the Wilcoxon signed rank test. RESULTS: D at was significantly different from D ct (P = 0.031), indicating that the time course of cTE0 was significantly different from that of blood oxygenation-weighted images (T2* and aTE45). CONCLUSION: The effect of blood oxygenation could be minimized using cTE0. Thus, signal intensity changes of cTE0 reflected changes in blood volume more specifically.
PURPOSE: Separate assessment of changes in blood oxygenation and blood volume is required in blood oxygen level-dependent (BOLD) imaging. We developed a calculated echo time (TE) imaging technique designed to minimize effects of blood oxygenation and to evaluate blood volume specifically. MATERIALS AND METHODS: Dynamic 3T multi-echo BOLD images of calf muscle were acquired from six healthy volunteers by use of a cuff-compression model. Calculated TE images at TE = 0 ms (cTE0) and T2* map (T2*) were calculated from acquired multi-echo images. The time courses of the mean value for the entire calf muscles in cTE0, in acquired BOLD images at TE = 45.2 ms (aTE45), and in T2* were obtained. The Euclidean distances between the two pairs of time courses were calculated: distance between aTE45 and T2* (D at), and that between cTE0 and T2* (D ct). The difference between D at and D ct was tested by use of the Wilcoxon signed rank test. RESULTS: D at was significantly different from D ct (P = 0.031), indicating that the time course of cTE0 was significantly different from that of blood oxygenation-weighted images (T2* and aTE45). CONCLUSION: The effect of blood oxygenation could be minimized using cTE0. Thus, signal intensity changes of cTE0 reflected changes in blood volume more specifically.
Authors: Bjoern Jacobi; Georg Bongartz; Sasan Partovi; Anja-Carina Schulte; Markus Aschwanden; Alan B Lumsden; Mark G Davies; Matthias Loebe; Georg P Noon; Sasan Karimi; John K Lyo; Daniel Staub; Rolf W Huegli; Deniz Bilecen Journal: J Magn Reson Imaging Date: 2012-06 Impact factor: 4.813
Authors: Hans Peter Ledermann; Hanns-Georg Heidecker; Anja-Carina Schulte; Christoph Thalhammer; Markus Aschwanden; Kurt A Jaeger; Klaus Scheffler; Deniz Bilecen Journal: Radiology Date: 2006-09-18 Impact factor: 11.105
Authors: Erin K Englund; Michael C Langham; Cheng Li; Zachary B Rodgers; Thomas F Floyd; Emile R Mohler; Felix W Wehrli Journal: J Cardiovasc Magn Reson Date: 2013-08-19 Impact factor: 5.364