Abstract: According to one embodiment, a magnetic resonance imaging apparatus includes a static magnetic-field generating unit, a gradient magnetic-field generating unit, a plurality of metal shim plates in a plate shape, and a shim holding unit. The metal shim plates adjust uniformity of the static magnetic field. The shim holding unit holds the metal shim plates in a layered state. Each of the metal shim plates includes a convex having a certain angle at a certain position, and the metal shim plates are layered such that the convex of each one metal shim plate comes into contact with a back of the bent convex of another metal shim plate.

Abstract: By using a temperature monitor, a coil-dedicated chiller measures an amount of change in temperature of cooling water flowing out from a cooling pipe of a gradient magnetic field, determines an amount of change in temperature of cooling water to be flowed into the cooling pipe in accordance with the measured amount of change in temperature of the cooling water; and changes the temperature of cooling water to be flowed into the cooling pipe of the gradient magnetic field based on the determined amount of change in temperature.

Abstract: Provided is a gradient coil capable of suppressing generation of an unnecessary magnetic field component while ensuring the readiness of conducting wire winding work. The gradient coil includes a cylindrical bobbin round which the conducting wire is wound; and a winding part formed by winding the conducting wire round the bobbin by a plurality of turns, wherein the winding part has a first winding part in which the conducting wire is wound round the bobbin orthogonal to the axis of the bobbin in a circumferential direction of the bobbin and a second winding part in which the conducting wire is spirally wound round the bobbin, skewing relative to the axis of the bobbin in the circumferential direction of the bobbin.

Abstract: In an MRI apparatus, a detecting unit that includes a thermographic imaging equipment and a normal imaging camera detects a change in temperature of an imaging space from outside of the imaging space. A judging unit judges whether the imaging space has a point at a temperature greater than a threshold TH, and if the judging unit judges the imaging space has such a point with a temperature greater than the threshold, the apparatus stops the sequence that applies a gradient magnetic field to the subject.

Abstract: A feedforward control unit predicts the maximum value of the temperature of a gradient coil based on a power duty and a scan time of a pulse sequence, and a present temperature of the gradient coil. When the maximum value exceeds a predetermined upper limit, the feedforward control unit then instructs a temperature adjusting unit to start a water circulation in a chiller at the start of a prescan, and the temperature adjusting unit starts the water circulation based on the instruction.

Abstract: Provided is a gradient coil capable of suppressing generation of an unnecessary magnetic field component while ensuring the readiness of conducting wire winding work. The gradient coil includes a cylindrical bobbin round which the conducting wire is wound; and a winding part formed by winding the conducting wire round the bobbin by a plurality of turns, wherein the winding part has a first winding part in which the conducting wire is wound round the bobbin orthogonal to the axis of the bobbin in a circumferential direction of the bobbin and a second winding part in which the conducting wire is spirally wound round the bobbin, skewing relative to the axis of the bobbin in the circumferential direction of the bobbin.

Abstract: A magnetic resonance imaging apparatus includes gradient magnetic coil, each having a plurality of line members wound in a predetermined winding pattern.

Abstract: A magnetic resonance imaging apparatus includes a static magnetic field magnet which generates a static magnetic field, a gradient coil unit which generates a gradient magnetic field for overlapping with the static magnetic field, a shim unit which is disposed between the static magnetic field magnet and the gradient coil unit to control the static magnetic field, and a heat shielding member which is disposed between the gradient coil unit and the shim unit to shield a radiant heat of the gradient coil unit.

Abstract: A magnetic resonance imaging apparatus includes a static magnetic field magnet which generates a static magnetic field, a gradient coil unit which generates a gradient magnetic field for overlapping with the static magnetic field, a shim unit which is disposed between the static magnetic field magnet and the gradient coil unit to control the static magnetic field, and a heat shielding member which is disposed between the gradient coil unit and the shim unit to shield a radiant heat of the gradient coil unit.

Abstract: There is provided a magnetic resonance imaging apparatus, including a gantry which has a gradient magnetic coil generating a gradient magnetic field to be applied to a subject in a magnetostatic field, a bed which allows a top board, on which the subject is placed, to slide in a longitudinal direction, a pulse applying unit which applies a high-frequency pulse to the subject, and a high-frequency coil which detects a magnetic resonance signal generated from the subject by applying the gradient magnetic field and the high-frequency pulse, in which the gradient magnetic coil includes a plurality of line members wounded in a predetermined winding pattern, a first resin material filled in gaps between the plurality of line members, and a second resin material which has higher thermal conductivity than that of the first resin material and is filled in gaps formed between the line members by winding at least one line member of the plurality of line members.

Abstract: A gradient coil or shield coil includes a first gradient coil part and a second gradient coil part having at least one different characteristic of (a) intensity of gradient magnetic field, (b) slew rate, (c) linearity and/or (d) changing rate of the magnetic field (as compared to characteristics of the first gradient coil part. In another aspect, a gradient coil includes a first portion close to a center of the gradient coil, a second portion which is outside of the first portion and which has a lower winding density than the first portion and a third portion which is outside of the second portion and which has a higher winding density than the second portion.

Abstract: A gradient coil or shield coil includes a first gradient coil part and a second gradient coil part having at least one different characteristic of (a) intensity of gradient magnetic field, (b) slew rate, (c) linearity and/or (d) changing rate of the magnetic field (as compared to characteristics of the first gradient coil part. In another aspect, a gradient coil includes a first portion close to a center of the gradient coil, a second portion which is outside of the first portion and which has a lower winding density than the first portion and a third portion which is outside of the second portion and which has a higher winding density than the second portion.

Abstract: A gradient coil for magnetic resonance imaging (MRI) has an elliptic cylindrical first coil and a second coil arranged coaxially to the first coil. The second coil is located outside the first coil in the radial direction thereof. The second coil is either elliptic-cylindrical or cylindrical. Winding positions of wires of the second coil are determined so that a magnetic field created outside the second coil by the first coil is cancelled out. Practically, circumferential current densities of the first and second coils are expressed by weighted even and odd functions. Ratios between weights of the second and first coils are then determined on values derived from the number of waves in the coil axial direction and a flatness rate of the ellipse. The winding positions of wires of the second coil are determined on the values.

Abstract: A gradient coil for magnetic resonance imaging (MRI) ha an elliptic cylindrical first coil and a second coil arranged coaxially to the first coil. The second coil is located outside the first coil in the radial direction thereof. The second coil is either elliptic-cylindrical or cylindrical winding positions of wires of the second coil are determined so that a magnetic field created outside the second coil by the first coil is cancelled out. Practically, circumferential current densities of the first and second coils are expressed by weighted even and odd functions. Ratios between weights of the second and first coils are then determined on values derived from the number of waves in the coil axial direction and a flatness rate of the ellipse. The winding positions of wires of the second coil are determined on the values.

Abstract: A curved metal plate is adhered to an outer surface of a cylindrical jig of the same shape, the metal plate is cut along the spiral coil winding pattern, the unnecessary metal portion other than the coil winding is peeled off from the jig to leave only the coil winding on the jig, an adhesive is applied on the coil winding, and an insulating sheet is covered over the jig (the coil winding thereon). After the coil winding is adhered to the insulating sheet, the insulating sheet (together with the coil winding) is peeled off from the jig. As a result, a saddle coil adhering the spiral coil winding to the inner side of the curved cylindrical insulating sheet is manufactured. According to such manufacturing method, without requiring huge equipment such as drying furnace, the saddle coil having a desired winding pattern with high precision can be manufactured in a short time and at low cost.

Abstract: A magnetic resonance imaging apparatus generates an MR signal from an object to be examined by applying a gradient field pulse generated by a gradient field coil and a high-frequency magnetic field pulse generated by a high-frequency coil onto the object in a static field generated by a static field magnet, and reconstructs an image on the basis of the MR signal. The gradient field coil is housed in a sealed vessel. A cable extending from an external power supply and connected to the gradient field coil has predetermined flexibility.

Abstract: Provided is a self-shielded gradient coil unit with no useless electromagnetic induction, which is capable of increasing the efficiency of shielding. The unit comprises an X-channel, Y-channel, and Z-channel gradient coil assemblies. Each of the X-, Y- and Z-channel gradient coil assemblies has a pair of a main coil and a shield coil. The main coil has a first patterned winding formed by a first conductive wire wound on a predetermined pattern, and the shield coil has a second patterned winding formed by a second conductive wire wound on the predetermined pattern. A shielding magnetic field provided by the shield coil preventing the gradient provided by the main coil from leaking out of the unit. At least one of the first and second conductive wires is divided at the predetermined pattern into a plurality of wires.

Abstract: An MRI system is provided for improving the magnetic coupling and positional relationship between gradient coils and shim coils, thus simplifying positioning of the coils (retention of orthogonality), designing an MRI system compactly, and reducing cost. An MRI system comprises a magnet generating a static magnetic field and a gradient coil unit generating a gradient magnetic field superposed on the static magnetic field. The gradient coil unit is formed into a substantially cylindrical shape having an outer circumferential surface, and shields the gradient magnetic field from being leaked out into a radially outer space. The MRI system further comprises a shim coil unit generating a correcting magnetic field homogenizing the static magnetic field. The shim coil unit is mounted on the outer circumferential surface of the gradient coil unit in common serving as a bobbin for the shim coil unit.

Abstract: Disclosed is an RF magnetic shield for magnetic resonance imaging apparatus having a gradient coil and an RF coil allocated in a generally cylindrical magnet of the apparatus. The RF magnetic shield comprises conductive shielding plate members, disposed between the gradient coil and the RF coil, through which long slits are formed, and capacitors connected to both the longitudinal ends of the slits, respectively. Each of the capacitors consists of a multilayer capacitor, which is a larger capacitance and is continuously and electrically connected to both the longitudinal ends of the respective slits.