Question: What is the description of T1p (T1rho) MRI?
About the article "Magnetic resonance imaging", section "T1rho MRI".

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T1ρ (T1rho): Molecules have a kinetic energy that is a function of the temperature and is expressed as translational and rotational motions, and by collisions between molecules.
The moving dipoles disturb the magnetic field but are often extremely rapid so that the average effect over a long time-scale may be zero.
However, depending on the time-scale, the interactions between the dipoles do not always average away.
At the slowest extreme the interaction time is effectively infinite and occurs where there are large, stationary field disturbances (e.g., a metallic implant).
In this case the loss of coherence is described as a "static dephasing".
T2* is a measure of the loss of coherence in an ensemble of spins that includes all interactions (including static dephasing).
T2 is a measure of the loss of coherence that excludes static dephasing, using an RF pulse to reverse the slowest types of dipolar interaction.
There is in fact a continuum of interaction time-scales in a given biological sample, and the properties of the refocusing RF pulse can be tuned to refocus more than just static dephasing.
In general, the rate of decay of an ensemble of spins is a function of the interaction times and also the power of the RF pulse.
This type of decay, occurring under the influence of RF, is known as T1ρ.
It is similar to T2 decay but with some slower dipolar interactions refocused, as well as static interactions, hence T1ρ≥T2.
The MRI has become the most frequently used study to diagnose spinal stenosis.
The MRI uses magnetic signals (instead of x-rays) to produce images of the spine.
MRIs are helpful because they show more structures, including nerves, muscles, and ligaments, than seen on x-rays or CT scans.
MRIs are helpful at showing exactly what is causing spinal nerve compression. 
  Ruby (hardware description language)  Ruby (programming language)  Ruby an early development name for Visual Basic  Ruby MRI, the C reference implementation of the Ruby language  
Cinedefecography is a technique that is an evolution of defecagography.
The defecation cycle is recorded as a continuous series rather than individual still radiographs.
More recent techniques involve the use of advanced, cross-sectional imaging modalities such as magnetic resonance imaging.
This is known as dynamic pelvic MRI, or MRI proctography.
The MRI proctography also called MRI defecography is not as efficient as conventional x-ray defecography for some problems. 
For each pair of antihomologous points of two circles exists a third circle which is tangent to the given ones and touches them at the antihomologous points.
The opposite is also true — every circle which is tangent to two other circles touches them at a pair of antihomologous points.
Let our two circles have centers O1 and O2 (Figure 5).
E is their external homothetic center.
We construct an arbitrary ray from E which intersects the two circles in P, Q, P′ and Q′.
Extend O1Q and O2P′ until they intersect in T1.
It is easily proven that triangles O1PQ and O2P′Q′ are similar because of the homothety.
They are also isosceles because O1P=O1Q (radius), therefore∠O1PQ=∠O1QP=∠O2P′Q′=∠O2Q′P′=∠T1QP′=∠T1P′Q.
Thus T1P′Q is also isosceles and a circle can be constructed with center T1 and radius T1P′=T1Q.
This circle is tangent to the two given circles in points Q and P′.
The proof for the other pair of antihomologous points (P and Q′), as well as in the case of the internal homothetic center is analogous.
If we construct the tangent circles for every possible pair of antihomologous points we get two families of circles - one for each homothetic center.
The family of circles of the external homothetic center is such that every tangent circle either contains "both" given circles or none (Figure 6).
On the other hand the circles from the other family always contain only one of the given circles (Figure 7).
All circles from a tangent family have a common radical center and it coincides with the homothetic center.
To show this let's consider two rays from the homothetic center, intersecting the given circles (Figure 8).
Two tangent circles "T1" and "T2" exist which touch the given circles at the antihomologous points.
As we've already shown these points lie on a circle "C" and thus the two rays are radical axes for "C"/"T1" and "C"/"T2".
Then the intersecting point of the two radical axes must also belong to the radical axis of "T1"/"T2".
This point of intersection is the homothetic center E. If the two tangent circle touch collinear pairs of antihomologous point — as in Figure 5 — then because of the homothetyformula_13.
Thus the powers of E with respect to the two tangent circles are equal which means that E belongs to the radical axis.