Measured specific gravity, predicted specific gravity and total body water relationships in normal young men

Hyperkalemic Periodic Paralysis and Permanent Weakness: 3-T MR Imaging Depicts Intracellular23Na Overload—Initial Results

“…MUSCULOSKELETAL IMAGING: MR Depiction of 23 Na Overload in Hyperkalemic Periodic Paralysis Amarteifio et al a weighting toward intracellular sodium (20). In an analysis on paramyotonia, an allelic disorder, noninvasive 23 Na MR imaging techniques at 1.5-T for detecting changes of the Na + signal in muscular tissue after provocation were implemented (16).…”

“…MUSCULOSKELETAL IMAGING: MR Depiction of 23 Na Overload in Hyperkalemic Periodic Paralysis Amarteifio et al a weighting toward intracellular sodium (20). In an analysis on paramyotonia, an allelic disorder, noninvasive 23 Na MR imaging techniques at 1.5-T for detecting changes of the Na + signal in muscular tissue after provocation were implemented (16). Also, these techniques have been successfully refined to aid qualitative visualization of changes of the muscular Na + amount in patients with hypokalemic periodic paralysis in a state of severe permanent weakness (9,20).…”

“…In the current study, IR 23 Na MR imaging sequences were included to allow for a reduction of signal emitted by blood vessels and muscular edema. The rationale was a better visualization of intracellular sodium content changes that are primarily responsible for muscle weakness.…”

“…Recent studies have shown the potential of 23 Na MR imaging for quantification of total sodium amount in human muscle (12). A central problem in 23 Na MR imaging is that the signal emitted from muscle tissue is roughly 50 000 times smaller than the signal received from standard proton (hydrogen 1 [ 1 H]) MR imaging (13). The short T2 relaxation time of 23 Na in (muscular) tissue causes a low signal-to-noise ratio when conventional measuring times are used.…”

“…A central problem in 23 Na MR imaging is that the signal emitted from muscle tissue is roughly 50 000 times smaller than the signal received from standard proton (hydrogen 1 [ 1 H]) MR imaging (13). The short T2 relaxation time of 23 Na in (muscular) tissue causes a low signal-to-noise ratio when conventional measuring times are used. This is still the case when newer density-adapted threedimensional radial acquisition techniques are used to improve the results (14,15).…”