Dynamic Gd-DTPA-enhanced MR imaging of the kidney: experimental results.

Abstract

To determine the normal appearance of dynamic enhanced renal magnetic resonance (MR) images, 25 rabbits were injected with Gd-DTPA and 32 consecutive gradient-recalled images were acquired. Several rabbits were also imaged in dehydrated (five animals) and overhydrated (seven animals) states. A reproducible renal enhancement pattern is observed that can be divided into three phases. During the first phase, a peripheral dark band appears, probably representing arrival of Gd-DTPA within the arterioles and vasa recta. The second phase begins as a second dark band migrating centripetally toward the medulla; this likely represents the concentration of Gd-DTPA in the descending limb of the loop of Henle. The third phase is characterized by a gradual darkening in the papilla, probably caused by concentration of Gd-DTPA within the collecting ducts. Hydration status influences the duration of these phases. These observations can be explained by the anatomy and physiologic characteristics of the nephron, as well as the MR characteristics of Gd-DTPA at different concentrations.

Glomerular filtration rate measured using the Patlak plot technique and contrast‐enhanced dynamic MRI with different amounts of gadolinium‐DTPA

“…This phenomenon has been described in previous studies using GRE sequences. Choyke et al (14) found a lower MR signal when they measured Gd-DTPA concentrations above 12 mmol Gd-DTPA per liter using a GRE sequence with a flip angles of both 40°and 90°. Testing the MR sequence used in the present study, we found proportionality between the MR signal and Gd-DTPA concentration up to approximately 10 -20 mmol Gd-DTPA per liter (1).…”

Imaging Acute Renal Failure with Polyamine Dendrimer-Based MRI Contrast Agents

“…Functional MRI of the kidneys began as a field with the introduction of gadolinium-DTPA (Gd-DTPA) also known as gadopentatate dimeglumine in the 1980s [4, 5]. It was quickly realized that, as a small molecule <1 kDa, Gd-DTPA was filtered at the glomerulus and neither secreted nor reabsorbed in the tubules.…”

Wireless Amplified Nuclear MR Detector (WAND) for High-Spatial-Resolution MR Imaging of Internal Organs: Preclinical Demonstration in a Rodent Model

“…Before the injection of gadopentetate dimeglumine, little intracortical contrast enhancement was observed in the renal cortex, except for the blood vessels, which appeared as bright spots on the zoomed-in image in Figure 3, C1. Twenty minutes after injection of a low-dose bolus of gadopentetate dimeglumine at 5 mmol/kg, bright strips appeared on the image in Figure 3, D1, as gadopentetate dimeglumine was filtered out of blood and became sufficiently concentrated inside renal tubules (19). This contrast enhancement persisted for the entire imaging session, possibly due to slow excretion of gadopentetate dimeglumine for a rat under deep anesthesia.…”

“…All contrast agents were administered through tail veins. Dilute gadopentetate dimeglumine concentrates in the renal tubules during the urine formation (19) and increases the signal intensity of the image, whereas cationized ferritin binds specifically to the basement membrane of glomeruli (20) and reduces the image intensity. To quantitatively identify contrast-enhanced regions, the intensity value of each pixel was compared with the local average and their difference was divided by the noise floor to obtain the deviation-to-noise ratio (DNR).…”