When a protocol is given in mmol per kilogram, you multiply the per-kilogram dose by the patient's weight to get the total mmol. For an 80 kg patient, 0.1 mmol/kg × 80 kg equals 8 mmol. So the total dose is 8 mmol. This reflects that the dose scales directly with weight: doubling weight would double the total amount at the same per-kilogram dose. If you got a different number, it would mean using a different per-kilogram dose or a different weight, not the 0.1 mmol/kg specified.

Net Magnetization Vector is the standard term for the combined magnetic moment of all nuclei in a region, represented as a vector M with components along the axes. In MRI, the signal you detect comes from the transverse component of this vector, Mxy, which precesses around the main magnetic field B0. At rest, the NMV points along B0 (the longitudinal direction). When a radiofrequency pulse is applied, the NMV is tipped away from the z-axis, creating transverse magnetization that produces the MR signal. The other terms aren’t used in MRI: Nuclear Magnetic Vector isn’t a conventional term, Normal Magnetization Value isn’t a standard concept, and Neuromagnetic Vector refers to brain magnetic fields measured by MEG, not the MR signal.

RF pulse timing sets how tissues recover and dephase between excitations, which is the primary way image contrast is formed. After each pulse, tissues with different T1 and T2 relaxation times recover longitudinal magnetization and accumulate transverse magnetization at different rates. The repetition time (TR) and, if used, inversion time (TI) determine how much recovery has occurred before the next excitation, shaping T1-weighted contrast. The echo time (TE) controls how much transverse magnetization has decayed before signal readout, shaping T2-weighted contrast. Inversion recovery sequences, where a 180-degree pulse is followed by a defined TI, exploit this timing to null or emphasize signals from specific tissues, producing pronounced contrast differences. Other aspects like signal-to-noise ratio depend on factors such as coil design, field strength, voxel size, and averaging; acquisition speed is set by sequence timing and hardware constraints beyond just RF timing; and gradient performance relates to hardware capabilities and timing of gradient waveforms rather than RF timing alone.

Proton density weighting emphasizes the number of mobile hydrogen protons present per unit volume in tissue. In practice, this is achieved by using a long repetition time to minimize T1 effects and a short echo time to minimize T2 differences, so the image contrast mostly reflects how many protons are available to produce signal rather than how quickly they relax. Therefore tissues with more hydrogen protons—typically water-rich areas like CSF or edema—appear brighter, while tissues with fewer protons appear darker. Magnetic susceptibility and relaxation-time effects are not the primary drivers of PD-weighted contrast.