Renal diffusion and BOLD MRI in experimental diabetic nephropathy. Blood oxygen level-dependent.
OBJECTIVE
To investigate the possibility of using combined blood oxygen level-dependent (BOLD) imaging and diffusion-weighted imaging (DWI) to detect pathological and physiological changes in renal tissue damage of the kidney induced by chronic renal hyperfiltration.


METHODS
The apparent diffusion coefficient (ADC) and the T(2)* value within the inner compartments of the kidneys of 17 rats with diabetes mellitus were compared with the results obtained from a control group (N = 16). The influence of dynamic changes of the renal function on the blood-oxygen saturation was evaluated by comparing the T(2)* values before and after the active reduction of tubular transport by furosemide injection.


RESULTS
All compartments of the diabetic kidney showed significantly (P < 0.05) lower T(2)*-values compared to the control group. In particular, the very low values in the outer stripe (OS) of the outer medulla (OM) (T(2)*-normal: 69.4 +/- 10.9 msec; T(2)*-diabetic: 51.4 +/- 13.9 msec) indicated either hypoxia due to hyperfiltration, or renal blood volume changes. Diffusion imaging of the same area showed significantly lower ADC values (ADC-normal: 1.45 +/- 0.26; ADC-edema: 1.19 +/- 0.25 [10(-9)m(2)/s]) that correlated with pathological findings on histopathology. The injection of furosemide significantly (P < 0.05) increased T(2)* in all compartments of both populations while the ADC remained unchanged.


CONCLUSIONS
BOLD-contrast imaging appears to be able to depict tissue at risk from ischemia by revealing information about the balance between tubular workload and delivery of oxygen, and thus may reflect a measure of the reserve capacity. The diffusion measurements apparently reveal complementary information. Although ADC imaging is not sensitive to the current energy metabolism, it appears toreflect the pathological changes within the issue. Therefore, ADC measurements may be a sensitive indicator of the severity of ischemic lesions.
Ries
Mario
M
Résonance Magnétique des Systèmes Biologiques, Université Victor Segalen-Bordeaux, France.
Basseau
Fabrice
F
Tyndal
Benoît
B
Jones
Richard
R
Deminière
Colette
C
Catargi
Bogdan
B
Combe
Christian
C
Moonen
Chrit W T
CW
Grenier
Nicolas
N
D000818:Animals; D003920:Diabetes Mellitus / Q000139:chemically induced* / Q000473:pathology*; D003928:Diabetic Nephropathies / Q000139:chemically induced* / Q000473:pathology*; D004232:Diuretics / Q000008:administration & dosage; D005665:Furosemide / Q000008:administration & dosage; D007668:Kidney / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D051381:Rats
D004232:Diuretics; D005665:Furosemide