Timeresolved Cortical and Medullary Enhancement

Whereas contrast arrival time at the cortex is similar for normal and ischemic kidneys, the transit time from cortex to medulla is much longer (40 seconds vs 15 seconds) for kidneys with renal vascular disease and decreased function [42]. Thus, medullary enhancement in ischemic kidneys is characteristically delayed and decreased compared to normal kidneys. Recently Lee et al. reported us

Table 4. Sensitivity and specificity of contrast-enhanced renal MRA for assessing transplant renal arteries

Technique

Author

Year

# Patients

Sensitivity (%)

Specificity (%)

TOF

Gedroyc [86]

1992

50

83

97

3D TOF

Smith [6]

1993

34

100

95

3D Gd

Johnson [87]

1997

11

67

88

3D PC

60

76

2D TOF

47

81

3D Gd + PC

100

100

3D Gd

Luk [88]

1999

9

100

3D Gd

Ferrieros [89]

1999

24

100

98

3D Gd

Chan [90]

2001

17

100

75

3D Gd

Huber [91]

2001

41

100

100

ing MR renography with low dose Gd contrast (2 mL) to assess contrast enhancement of renal cortex and medulla [43]. After an initial vascular phase (20 seconds), dysfunctional kidneys demonstrate markedly less medullary enhancement during the tubular phase (1 to 4 minutes), reflecting diminished glomerular filtration.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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