Calyceal transit time

For each patient the key features derived from MR urography include calculation of differential renal function (both volume and Patlak) (vDRF and pDRF), signal versus time curves for each kidney and the aorta, individual kidney GFR index of each kidney, concentration and excretion from each compartment, renal and calyceal transit times and overall anatomic diagnosis. It is important to understand that we have two methods to determine the differential renal function one based on volume and one based on the individual kidney GFR as determined by the Patlak plot. In most cases these are symmetric however, when there is a difference in these two measures of DRF it implies a change in renal hemodynamics that may ultimately provide information about which kidneys will benefit from surgery. 

The parameters routinely assessed by MR urography include the overall anatomic diagnosis, vDRF and pDRF, renal and calyceal transit times, signal intensity versus time curves and individual GFR index for each kidney. 

The calyceal transit time is the time it takes for the contrast to pass through the kidney, i.e., from... 

Fig.1.2.1a-f. Normal MR urogram in 3-month-old boy with antenatal hydronephrosis. Images a-c show same slice from each of three separate volume acquisitions, whereas d-f show MIP projections derived from the same three separate time points, a and d show the cortical phase, b and e were acquired 60 s later and demonstrate enhancement of both the cortex and medulla with the signal intensity of the medulla exceeding the cortex, c and f were acquired 115 s after the vascular phase and show excretion into the calyces, renal pelvis and ureters. The renal transit time was 2 min and 20 s bilaterally and the volumetric DRF was 51 49... 

Hydronephrotic kidneys that cannot accommodate a fluid challenge develop signs of decompensation on MR urography. These include a delayed, dense nephrogram, delayed calyceal and renal transit times and a difference between the pDRF and vDRF >4. 

Roselle methanolic and aqueous extracts have been reported to have antispasmodic activity on intestinal and uteral muscles as well as anthelmintic (tapeworm) properties. Extracts have been shown to both stimulate and inhibit isolated rabbit intestine. An aqueous extract of the calyces has been found to decrease intestinal motility in intact rats, as well as the oral-caecal transit time in dogs. ... 

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