Abstract: To suppress the image quality deterioration due to respiratory motion and changes thereof, and improve the data acquisition rate. An MRI device according to the present invention repeats a main measurement in a predetermined unit, and performs a navigation measurement to acquire one or a plurality of the navigator echoes between the measurements in the temporally adjacent two predetermined units, and performs determination as to whether to continue or discontinue the main measurement and determination as to whether to discard immediately prior measurement data. In the determination, at least two navigator echoes are used, and by using a position of a site to be monitored by the navigation measurement and a displacement width serving as a reference of the displacement stability, whether the position and the displacement width satisfy a reference displacement and a reference displacement width, which have been obtained in advance, is determined.

Abstract: Imaging failure of a positioning image due to the difference in the position or the size of a subject placed in the examination space is prevented, and accordingly, the extension of the examination time is prevented. A pre-scan for appropriately setting the imaging position for positioning imaging is automatically performed prior to the positioning imaging and the main imaging of an MRI apparatus, and a region where an examination part of a subject is present (the extent of the examination part) is detected using the measurement data. By using the detected extent of the examination part, it is possible to subsequently determine the imaging position or calculate the scan parameters used for imaging.

Abstract: Imaging failure of a positioning image due to the difference in the position or the size of a subject placed in the examination space is prevented, and accordingly, the extension of the examination time is prevented. A pre-scan for appropriately setting the imaging position for positioning imaging is automatically performed prior to the positioning imaging and the main imaging of an MRI apparatus, and a region where an examination part of a subject is present (the extent of the examination part) is detected using the measurement data. By using the detected extent of the examination part, it is possible to subsequently determine the imaging position or calculate the scan parameters used for imaging.

Abstract: To suppress the image quality deterioration due to respiratory motion and changes thereof, and improve the data acquisition rate. An MRI device according to the present invention repeats a main measurement in a predetermined unit, and performs a navigation measurement to acquire one or a plurality of the navigator echoes between the measurements in the temporally adjacent two predetermined units, and performs determination as to whether to continue or discontinue the main measurement and determination as to whether to discard immediately prior measurement data. In the determination, at least two navigator echoes are used, and by using a position of a site to be monitored by the navigation measurement and a displacement width serving as a reference of the displacement stability, whether the position and the displacement width satisfy a reference displacement and a reference displacement width, which have been obtained in advance, is determined.

Abstract: To provide a method for purifying tetrafluoroethylene by removing, from tetrafluoroethylene containing a polymerization inhibitor, the polymerization inhibitor by adsorption. A method of bringing tetrafluoroethylene containing a polymerization inhibitor into contact with a silica gel containing a metal salt in an amount of from 250 to 100,000 mass ppm as calculated as metal atoms to remove the polymerization inhibitor by adsorption, and the metal salt is preferably a salt of a metal of Group 3 to 13 of the Periodic Table, more preferably a salt of a metal of Group 8 to 10 of the Periodic Table. For example, as the metal salt, a salt of at least one metal selected from the group consisting of iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum may be used.

Abstract: To provide a method for purifying tetrafluoroethylene by removing, from tetrafluoroethylene containing a polymerization inhibitor, the polymerization inhibitor by adsorption. A method of bringing tetrafluoroethylene containing a polymerization inhibitor into contact with a silica gel containing a metal salt in an amount of from 250 to 100,000 mass ppm as calculated as metal atoms to remove the polymerization inhibitor by adsorption, and the metal salt is preferably a salt of a metal of Group 3 to 13 of the Periodic Table, more preferably a salt of a metal of Group 8 to 10 of the Periodic Table. For example, as the metal salt, a salt of at least one metal selected from the group consisting of iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum may be used.