Welcome to your MRI - A Name [Which of the following is the formula that is used to calculate blood flow velocity?] Velocity = Flow volume / Vessel area Velocity = Vessel area / Flow volume Velocity = Flow volume + vessel area Velocity = Vessel area - Flow volume None . [When a patient is placed in an external magnetic field, the number of unmatched hydrogen protons usually equals _______.] One billion One million Few per million Few per billion None . [Dephasing of the net vector in the transverse plane is known as _______.] Tl relaxation Spin-Lattice relaxation Longitudinal relaxation Spin-Spin relaxation None . [The magnitude of intra-voxel dephasing is dependent upon which factor(s)?] Degree of disruption in the flow Echo time Repetition time None of the above None . [To produce signal in a spin echo pulse sequence, blood flow must receive both the 90 degree and the 180 degree RF pulse.] True False None . [Phase mismapping artifact caused by respiratory motion can be decreased by which method?] Presaturation pulse Swapping phase and frequency direction Respiratory compensation All of the above None . [Image data with high spatial resolution is stored in which area of K space?] Outer lines Central lines Negative lines only Positive lines only None . [In plane pixel size can be determined by which of the following methods?] Dividing the FOV by the number phase and frequency steps Dividing the NEX by the FOV Dividing the TR by the NEX Dividing the TR by the slice thickness None . [Figure displays which type of relaxation curve?] TI relaxation curve T2 relaxation curve Inversion recovery curve None Comment . [Figure displays which type of relaxation curve?] T 1 relaxation curve Inversion recovery curve T2 relaxation curve T2* relaxation curve None Comment . [At a field strength of 1.0 tesla, the approximate Tl relaxation time for muscle tissue is ______.] 270ms 480ms 600ms 680ms None . [In conventional spin echo pulse sequences, how many phase encoding steps are achieved per TR?] 1 128 192 256 None . [The ratio that describes the constant at which any magnetic nucleus will precess in a 1 tesla magnet is known as _______.] Precessional ratio Magnetogyric ratio Gyromagnetic ratio Both B and C None . [The type of RF coil configuration that is used to image anatomical structures close to the surface of the patient is known as a _____.] Surface coil Quadrature coil Phased array coil Shim coil None . [The homogeneity of the external magnetic field is measured in what type of unit?] Tesla per centimeter Part per million Gauss per meter Megahertz None . [Which of the following is a biological effect unique to echo planar imaging?] Visual phosphenes Muscular twitches in face and back Tissue bums None of the above None . [During an inversion recovery pulse sequence, the time between the 180 degree inversion pulse and the 90 degree excitation pulse is known as ______. ] Echo time Repetition time Inversion time Reversion time None . [The area within the array processor where spatially located information is stored is known as _______.] Interspace Array space Fourier space K space None . [When pixel size increases, signal to noise ratio _______.] Increases Decreases Stays the same None . [The type of neoplasms in the head that enhance primarily due to their increase in vascularity are known as _____.] Intra axial neoplasms Extra axial neoplasms Metastatic neoplasms None of the above None . Time's up
