Functional evaluation of transplanted kidneys using arterial spin labeling MRI.

PURPOSE: To investigate non-contrast-enhanced arterial spin labeling (ASL) MRI for functional assessment of transplanted kidneys at 1.5 Tesla (T) and 3T. MATERIALS AND METHODS: This study was approved by the local ethics committee, and written informed consent was obtained from all participants. Ninety eight renal allograft recipients (mean age, 51.5 ± 14.6 years) were prospectively included in this study. ASL MRI was performed at 1.5T (n = 65) and 3T (n = 33) using a single-slice flow-sensitive alternating inversion recovery true-fast imaging with steady-state precession (FAIR True-FISP) sequence in the paracoronal plane. ASL perfusion was regional analyzed for the renal cortex on parameter maps. ASL was compared between patients with good or moderate allograft function (Group a; estimated glomerular filtration rate [eGFR] > 30 mL/min/1.73 m(2)) and patients with heavily impaired allograft function (Group b; eGFR ≤ 30 mL/min/1.73 m(2)) and correlated to renal function as determined by eGFR. RESULTS: ASL perfusion and eGFR were comparable at 1.5T (246.9 ± 66.8 mL/100 g/min and 41.9 ± 22.7 mL/min/1.73 m(2)) and 3T (236.5 ± 102.3 mL/100 g/min and 35.9 ± 22.9 mL/min/1.73 m(2)). ASL perfusion was significantly higher in group a (282.7 ± 60.8 mL/100 g/min) as compared to group b (178.2 ± 63.3 mL/100 g/min) (P < 0.0001). ASL perfusion values exhibited a significant correlation with renal function as determined by eGFR (r = 0.59; P < 0.0001). CONCLUSION: Cortical ASL perfusion values differ between patients with good or moderate allograft function and poor allograft function and correlate significantly with allograft function. Our results highlight the potential of ASL MRI for functional evaluation of renal allografts.

[A 58-year-old hypertensive patient with primary hyperaldosteronism and renal artery stenosis]. / 58-jähriger Patient mit primärem Hyperaldosteronismus und Nierenarterienstenose bei arterieller Hypertonie.

BACKGROUND: Secondary hypertension can rarely be caused by different disorders as shown in the present case with simultaneous occurrence of two possible causes. CASE REPORT: Magnetic resonance imaging findings of a 58-year-old patient showed an eccentric left renal artery stenosis of 60-70% and an inhomogeneous tumor of the left adrenal gland. After percutaneous transluminal angioplasty, elevated plasma aldosterone concentrations persisted. Adrenal vein sampling in the authors' hospital confirmed a primary hyperaldosteronism due to unilateral adenoma. Subsequently, unilateral laparoscopic adrenalectomy was performed. CONCLUSION: Atherosclerotic renal artery stenosis stimulates the renin-angiotensin system and thereby causes secondary hypertension. Furthermore, adrenal disorders that lead to abnormal aldosterone secretion, i.e., primary hyperaldosteronism, often result in secondary hypertension. Though the simultaneous occurrence of two potential causes of secondary hypertension is rare, it has to be considered for differential diagnosis and therapy. The presumed pathophysiological relevance should guide the order of therapeutic measures.