Obstructive nephropathy: evaluation with dynamic Gd-DTPA-enhanced MR imaging.

Abstract

The potential of dynamic gadolinium diethylenetriaminepentaacetic acid (DTPA)-enhanced magnetic resonance (MR) imaging for the examination of obstructive nephropathy was analyzed in 27 subjects (five healthy subjects, seven patients with dilated nonobstructed kidneys, six patients with acute obstruction, and nine patients with chronic obstruction) with use of a 1.5-T magnet. Morphologic findings were compared with quantitative analysis of temporal changes in signal intensity. Dynamic postcontrast images of the normal kidney demonstrated four phases of enhancement; cortical enhancement phase, early tubular phase, ductal phase, and excretory phase. The pattern of enhancement in dilated nonobstructed kidneys was similar to that in normal kidneys. In acutely obstructed kidneys, cortical enhancement was similar to that in normal kidneys (17% increase), but medullary enhancement was higher than normal, resulting in diminished corticomedullary differentiation. The early tubular phase was prolonged (until 2.5 minutes after injection), with delayed appearance of the ductal and excretory phases. In chronically obstructed kidneys, the increase in cortical intensity was less than that in normal kidneys (13% increase). The early tubular phase was prolonged, and the ductal phase was diminished or absent.

Diffusion tensor imaging of renal ischemia reperfusion injury in an experimental model

“…However, D true and P fraction values could still be reliably estimated by fitting Eq. [6] with the normalized DW signals acquired at high b-values (100-1000 s/mm 2 ) (11). Several limitations exist in the current study.…”

“…[6] with the ROI measurements of DW(b)/DW(0) at six b-values ranging from 100 to 1000 s/mm 2 using a least-square non-linear fitting in Matlab (Mathworks, Natick, MA). Two-tail paired Student's t-test was again employed to compare the D true and P fraction measurements in both kidneys of IR-injured animals.…”

Diagnosis of renovascular hypertension: feasibility of captopril-sensitized dynamic MR imaging and comparison with captopril scintigraphy.

“…In both responses, excretion of contrast material into the renal collecting system was suppressed. [11,[14][15][16] and, in humans, in obstructive uropathy [17,18] and extnaconponeal wave lithotnipsy [19]. In these pathologic situations, the tubular phase can be delayed or absent, confirming both the sensitivity and the absence of specificity of the method.…”

MR determination of glomerular filtration rate in subjects with solitary kidneys in comparison to clinical standards of renal function: feasibility and preliminary report

“…Other MR techniques that have been studied and proposed to estimate GFR include dynamic three-dimensional MR renography, the Rutland-Patlak plot technique (with both MR and CT), measurement of renal clearance of gadolinium-based contrast media from the extracellular fluid volume, and dynamic contrast-enhanced MRI perfusion (3,(9)(10)(11)(12)(13)(15)(16)(17)(18)(19)(20)(21)(22)(23). All of the above listed techniques are in the developmental stages and have their own limitations.…”

“…Functional techniques that have been described include MR renography (3,(9)(10)(11)(12)(13)(14), the arterio-venous extraction (A/V) technique (13,(15)(16)(17)(18)(19), the Rutland-Patlak plot techniques (20,21), the MR gadolinium slope clearance measurement technique (22) and the dynamic MR perfusion functional assessment (23,24). Since the iodinated contrast media and gadolinium contrast media in current use are nearly identical in their pharmacokinetics and renal handling, either CT or MR provide competitive utilization.…”